Printed circuit board

Abstract

A printed circuit board includes signal layers, ground layers, and a power layer, which are superposed. A closed trace is set along edges of each of the signal layers and the power layers. A number of vias are defined in each trace at intervals. Each via extends through the signal layers, the ground layers, and the power layer. Each via is electrically connected to the traces of the signal layers and the power layer, and electrically connected to the ground layers.

1. A printed circuit board comprising a plurality of signal layers, a plurality of ground layers, and a power layer, wherein the signal layers, the ground layers, and the power layer are superposed, a closed trace is set along edges of each of the signal layers and the power layer, a plurality of vias are defined in each closed trace at intervals, each via extends through the signal layers, the ground layers, and the power layer, each via is electrically connected to the closed traces of the signal layers and the power layer, and is electrically connected to the ground layers. 
     
     
       2. The printed circuit board of  claim 1 , wherein the width of each closed trace is about 20 mils. 
     
     
       3. The printed circuit board of  claim 1 , wherein the distance between two adjacent vias is about 40 mils. 
     
     
       4. The printed circuit board of  claim 3 , wherein the diameter of each via is less than the width of each closed trace. 
     
     
       5. The printed circuit board of  claim 1 , wherein the plurality of signal layers comprises a first signal layer, a second signal layer, and a third signal layer; the plurality of ground layers comprises a first ground layer and a second ground layer; wherein the first signal layer, the first ground layer, the second signal layer, the power layer, the second ground layer, and the third signal layer are superposed in that order.